A corporation not-for-profit has the officers described in its bylaws, and they are chosen by the board in accordance with the bylaws. A duly appointed officer may have one or more assistant officers if authorized by the bylaws. The bylaws of the corporation must delegate to one officer the customary responsibilities of an officer commonly known as "president", to one officer the customary responsibilities of an officer known as "secretary", and one officer the customary responsibilities of an officer commonly known as "treasurer". The responsibilities of secretary and treasurer may be held by the same person. An officer may be removed from office and his successor selected in the manner prescribed by the bylaws.